Four different dengue viruses are known to cause dengue hemorrhagic fever. Dengue hemorrhagic fever occurs when a person is bitten by a mosquito that is infected with the virus. The mosquito Aedes aegypti is the main species that spreads this disease.

There are more than 100 million new cases of dengue fever every year throughout the world. A small number of these develop into dengue hemorrhagic fever. Most infections in the United States are brought in from other countries. Risk factors for dengue hemorrhagic fever include having antibodies to dengue virus from an earlier infection.

Symptoms:

Early symptoms of dengue hemorrhagic fever are similar to those of dengue fever. But after several days the infected person becomes irritable, restless , and sweaty. These symptoms are followed by a shock -like state.

Bleeding appears as tiny spots of blood on the skin and larger patches of blood under the skin. Minor injuries can cause bleeding.

Shock can lead to death. If the person survives, recovery begins after a 1-day crisis period.